TY - JOUR
T1 - Competitive adsorption of Cu2+, Pb2+, Cd2+, and Zn2+ onto water treatment residuals
T2 - implications for mobility in stormwater bioretention systems
AU - Duan, Runbin
AU - Fedler, Clifford B.
N1 - Publisher Copyright:
© 2022 The Authors.
PY - 2022/9/1
Y1 - 2022/9/1
N2 - The lack of knowledge regarding competitive adsorption of heavy metal ions onto water treatment residuals has been hindering their reuse as a medium in stormwater bioretention systems. Competitive adsorption of copper(II), lead(II), cadmium(II), and zinc(II) onto polyaluminium chloride and anionic polyacrylamide water treatment residuals (PAC-APAM WTRs) was evaluated with different pH, temperature, initial concentration, and time. The competitive adsorption removal increased with the increase of pH and temperature. The analysis of the ratios of maximum adsorption capacity of a heavy metal ionic species in a multi-component system to that in a mono-component system (Qmix/Qmono) demonstrated that the coexisting ion had a negative effect on the adsorption of a metal ionic species. The Langmuir model provided a better fit, indicating that the adsorption could be a monolayer adsorption process. The modified Langmuir isotherm studies showed that the affinity order in the multi-component systems was Cu2+.Pb2+.Cd2+.Zn2+. The pseudo-second-order model better described the adsorption kinetics implying that the competitive adsorption behavior could be interpreted by diffusion-based mechanisms. This study contributed to a better understanding the mobility of those frequently occurring heavy metal ions in stormwater runoff in the PAC-APAM WTRs media layer of stormwater bioretention systems.
AB - The lack of knowledge regarding competitive adsorption of heavy metal ions onto water treatment residuals has been hindering their reuse as a medium in stormwater bioretention systems. Competitive adsorption of copper(II), lead(II), cadmium(II), and zinc(II) onto polyaluminium chloride and anionic polyacrylamide water treatment residuals (PAC-APAM WTRs) was evaluated with different pH, temperature, initial concentration, and time. The competitive adsorption removal increased with the increase of pH and temperature. The analysis of the ratios of maximum adsorption capacity of a heavy metal ionic species in a multi-component system to that in a mono-component system (Qmix/Qmono) demonstrated that the coexisting ion had a negative effect on the adsorption of a metal ionic species. The Langmuir model provided a better fit, indicating that the adsorption could be a monolayer adsorption process. The modified Langmuir isotherm studies showed that the affinity order in the multi-component systems was Cu2+.Pb2+.Cd2+.Zn2+. The pseudo-second-order model better described the adsorption kinetics implying that the competitive adsorption behavior could be interpreted by diffusion-based mechanisms. This study contributed to a better understanding the mobility of those frequently occurring heavy metal ions in stormwater runoff in the PAC-APAM WTRs media layer of stormwater bioretention systems.
KW - competitive adsorption
KW - heavy metals
KW - modified Langmuir isotherm
KW - multi-component systems
KW - polyaluminium chloride and anionic polyacrylamide water treatment residuals
KW - stormwater bioretention systems
UR - http://www.scopus.com/inward/record.url?scp=85139257766&partnerID=8YFLogxK
U2 - 10.2166/wst.2022.258
DO - 10.2166/wst.2022.258
M3 - Article
C2 - 36358035
AN - SCOPUS:85139257766
SN - 0273-1223
VL - 86
SP - 878
EP - 893
JO - Water Science and Technology
JF - Water Science and Technology
IS - 5
ER -